Calculations on fission gas behaviour in the high burnup structure

On the condition of UO2 nuclear fuel irradiated in a PWR to a burn-up in excess of 110 MWd/kgHM

“…This is still considerably higher than the temperature for the 9 cycle rod 12C3. An earlier version of the code gave similar results [15]. The uncertainty on the maximum calculated center temperatures during the last two irradiation cycles is of the order of ± 70 C.…”

Detailed characterisations of high burn-up structures in oxide fuels

“…They start around 0.2 wt% and reach rapidly values lower than 0.1 wt% of xenon. This value should be taken into account for modelling [31]. Slightly higher values are measured in the mid-radius MOX agglomerates and in the FBR fuels, with larger sub-grains and higher irradiation temperatures.…”

Evolution of porosity in the high-burnup fuel structure

“…The economic advantage of operating fuel at extended burnups has motivated a large scientific effort devoted to the characterization and modeling of the high-burnup fuel structure (HBS), with the purpose of understanding the modifications of the fuel thermal-mechanical performance occurring after restructuring [1][2][3]. Two key phenomena dominate the fuel behavior at high burnups: (1) the formation of sub-micron grains and (2) the presence of micrometer porosity [1].…”